Direct-connected burr-mill unit



Aug. 10,1926. 1,595,605

c. T. HIBBARD DIRECT CONNECTED BURR MILL UNIT 0 v Filed April 5, 1920 4 Sheets-Sheet 1 C) c) c343) 152 mania! IAZIMJTW/M/YAZQaAzJ Aug. I C. T. HIBBARD DIRECT CONNCTED BURR MILL UNIT Filed April 5, 1920 4 Sheets-Sheet 5 DIRECT CONNECTED BUBR MILL UNIT Filed April 5', 1920 4 Sheets-Sheet 4 50 as 4 25 49 L 5 A I j 33 as L F 4; 39 37 v '77 3'4 q 2 /3 36- 35 r 1 5 I [54 J0- f! I8 I 4a EVE/275e dvdlzssl'ewnweuzp plan view of the Patented, Aug. 10, 1926.

UNITED STATES PATENT OFFICE.

CHARLES TRUMAN HIBBARID, 0F

MINNEAPOLIS, MINNESOTA, ASSIGNOR, BY MESNE ASSIGNMENTS, TO ELECTRIC MACHINERY MFG. COMPANY, OF MINNEAIPOLIS,.

MINNESOTA, A CORPORATION OF MINNESOTA.

DIRECT-CONNECTED BUBR-MILL UNIT.

Application filed April '5, 1920. Serial No. 371,464.

One object of my invention is to provide an improved construction for a direct connected burr mill unit that will allow the operation of'the rotor at various displacements with reference to the center plane of the may be controlled at a point distant from the machine.

Another object is to provide electrical control such that all "upper burrs in one mill may be lifted simultaneously from various points distant from the machine.

WVith these and incidental objects in view,

the invention consists of certain novelfeatures of construction and combination of parts, the essential element-s of which are hereinafter described with reference to the drawings which accompany and .form a part of this specification: p

In the drawings, Figure 1 is a side elevation, partly in section, of my improved burr mill unit; Figure 2 is a side elevation taken at substantially 90 to that shown in Figure 1; Figure 3 is a detail plan view of the cockeye; Figure 4} is a section taken on the line 42-4, Figure 3; Figure 5 is a schematic'circuit showing the push button control; Figure 6 is a schematic wiring ing motor and magnetic clutch; Figure 7 is an enlarged detail, partly in section, of the reduction from the motor to the mechanism forlifting' the topburr; and Figure 8 is a same. 7 Thejpractice in the past in pperating burr mills has been to drive the mill from horiz'ontal motors and through belts, this practicenecessarily requiring a great deal more' room, and also necessarily subjecting the mill to more frequent shut-downs than if the mill consisted of a direct connected unit,

diagram of the liftlhe unit shown and described is designed primarily for grinding grain, but it will readily be seen that similar units can be used in the grinding of paint ingredients and other materials where the grinding features are analogous to that shown in the present invention.

It is customary to feed grain into the mill through the top stone, allow it to pass into a space between the two stones, and there be ground to the desired fineness, the ground grain passing to the perimeter of the stones and out through a suitable spout to the proper bins.

It hasbeen found in practice that when the supply of grain fails for any reason, the stones will strike and the surfaces be injured,

necessitating the resharpening of the stones which is a troublesome and expensiveoperation, and'is tobe avoided as much as possible.

So long as grain is fed to the stones there is no possibility'of the stones coming in contact and being injured. Hence it is ap parent that the best means of preventing the injury of the face of the stones would be to have some automatic device that would actuate upon the failure of the grain supply.

Also, as the stones will wear from ordinary use, suitable adjustment should be provided so the distance between the faces of the stones can be varied at will to take up tl1e wear and also to grind the grain to various degrees of fineness.

I accomplish the object desired by having the rotor of an electrical motor mounted on the same shaft as, that driving the revolving stone, which ordinarily is the upper stone.

From .the nature of the work and the speed at which the stone should be driven, a

typical speed being 225 R. P. M., the synchro ous motor lends itself readily to this particular work, and in ,the drawings :1 have shown such a motor as applied to and forming a part of the burr mill unit.

As shown in Figure l, the housing 1 supports the stator-2 and the magnetic face 3 of the stator is wider than the face 4 of the rotor, a typical case showing a difierence of one inch in width The rotor 5 drives the shaft 6 mounted in ball bearings 7 and 8, and which drives,

The bearing 8 is carried by a sleeve 9', which in turn is carried by threaded. engagement at 10 by the spider 111 Attached to, or forming a part of the sleeve 9 is a worm gear 12, the teeth 13 of which are straight so the worm can be raised or lowered a predetermined amount and still remain in engagement with the worm 14.

The worm 14, Figures 7 and 8, is driven by the worm gear 15, which in turn is driven by the worm 16, directly driven by a suitable motor 17 and the magnetic clutch 18 is provided, one member being carried by or forming a part of the worm gear 15, while the other member is splined to the worm shaft at 19.

Actuating current for the magnetic clutch is supplied through the slip rings 20 and it is evident that when the clutch is engaged the rotation of the motor 17 which is reversible, will cause the rotation of the sleeve 9', while the disengagement of the clutch will allow the rotation of the motor 17 without rotating the sleeve 9, and will also allow the rotation of the sleeve 9 through the bevel gears 21 and hand wheel 22, Figure .2.

Referring to Figure 1, the spout 23 has a flexible joint at 24 and is supported against gravity by a spring 25 which is of asuflicient' strength to maintain the contact 26 closed. unless grain is passing through the spout. When, however, grain is passing through the spout 23 the weight of the grain opens the contact 26 for a purpose hereinaftendescribed.

Referring now to Figure 6, direct current from a suitable source of supply 27 is supplied through a master switch 28 to the reversible compound wound direct current motor 17 through either the contactor switch 29 or the contactor switch 30, the switch 29 connecting circuits in such direction that the motor will rotate in the proper direction to lower the stone, and switch 30 controlling a circuit such that when closed the motor will rotate in the proper direction to lift the 7 stone.

From a suitable source of current supply,

preferably alternating current, at 31, the' contact 26 is closed.

eeaeoe lower the stone 10, Figure 1, the circuit as shown in the diagram being as follows: master switch 28, wire 40, contactor switch 29, wire 41, series field 42, wire 43, wire 44, contactor switch 29, wire 45, wire 46, armature 47, wire 48, contactor switch 29, wire 49, wire 50, master switch 28. From the series field 42 the shunt field 51 is connected to the right hand side of the master switch 28 through wire 52, wire 49 and 50. The contactor switch 30 when closed suppliesthe circuit to drive the motor inthe opposite direction, this circuit being as follows: master switch 28, wires 40, 53, contactor switch ,30, wires 54, 41, series field 42, wire 43, contactor switch 30, wire 55, wire 48, armature 47, wire 46, contactor switch 30, wire 50, to masterswitch 28. -The shunt field is con nected from one side of the series field to the master switch 28 through wires 52, 49, and 50 in the same manner as when contactor switch 29 is closed.

It will be noted from the circuits just traced that the current traverses the armas ture in the opposite direction when the contactor switch 30 is closed than when the contactor switch 29 is closed.

It will be readily understood, therefore, that when the grain supply passing through the spout 23, Figure 1, fails for any reason and the contact 26 is closed the motor 17 is rotated in such a direction that the sleeve 9 is lifted, and with it the rotor 5, shaft 9, and stone 10.

If the push button 33 is held closed for a considerable length of time or if the contact 26 remains closed for a considerable length of time the motor will continue to rotate until the shaft 6 has been-lifted up to such a height that the insulating ring 56 lifts the spring 57 from the contact spring 58, thereby opening the circuit from the source of supply 27 at 59, Figure 6.

Likewise if the motor is caused to drive the shaft in the reverse direction so as to lower the stone more than a predetermined amount, the contact spring 59' will be lifted from the contact 60, thereby opening the supply current at 61, Fi re 6.

The magnetic clutch 18 is actuated when either contactor switch 29 or 30 is closed, being in series with the series field 42 and in parallel with the armature 47, regardless of the direction inwhich the current traverses. the armature.

When the contactor switch 29 is closed the circuit for the magnetic clutch is as follows: main switch 28, wire 40, contactor switch 29, wire 41, series field 42, wire 43, wire 70, magnetic clutch 18, wlres 71 and 50, to the other side of the switch 28.

When the contactor switch 30 is closed the magnetic" clutch circuit is as follows: mam switch 28, wires 40, 53, contactor swltch 30, wires 54, .1, serie fie dfii, Wlfes the upper stone.

Also, that if the motor is not actuated the clutch is not actuated, thereby leaving the control of the raising or lowering mechanism manual instead of automatic.

.Inasmuchas the worm gear 12 is rotatable through the bevel gears 21 by means of 15 the hand Wheel 22, it is evident that the upper stone 10 may be raised .or lowered.

manually without the operation of the motor 17.

The raising and lovfiering of the stone manually'is ordinarily for the purpose of adjusting the distance between the two burrs and it is a simple matter for the operator to adjust the distance between the two burrs approximately by closing the push button 32 or 33, thereby movin the stone with the motor 17 and then maie his final adjustment by means of the hand wheel 22. Looking at Figure 1, it will be seen that the cockeye is supported on the shaft 6 with two collars 62, which in a typical case would each be one inch wide, anda third collar 63; in a typical case this collar would be two inches wide.

It is apparent, therefore, that by removing one or more of these collars and by the one inch adjustment provided in the lifting of the upper stone without moving the rotor out of its proper magnetic field, a vertical adjustment of four inches is provided for Looking at Figures 1, and 4, it will be seen; that the cockeye supports the upper stone on the ball point 64, and that the arm 65 of the driving spider plays loosely in the recesses 66 of the member 67, which directly drives the upper stone 10, this form of drive allowing the upper stone to. .seek its own plane of rotation. V

" Under some conditions it is necessary to be able to lift all of the upper burrs at the same time, and such a condition might arise when the man or men in charge of the plant might be in various positions around the bnilding.

I have, therefore, arranged means whereby all of the units in the plant can be put out of operation simultaneously by the lifting of the upper-burr .in each plant.

The push -button 33 for each of the units ,"in the plant, as represented by 33, 3,3 and 33 Figure 5 are s o wired that they may all be short-circuited by the actuation ofv either one of'push buttons 75, 75?, or 5..

It wi l be seen from Figure 551 center plane of said stator.

wires 76, and 77 lead to contact springs 78 and 79, respectively, and are then multipled to the contact springs-'78 and 79' of push button 75, contact springs 78 and 79 of push button 7 5 and contact springs 7 8 and 7 9 of push button 75 Eachof the contacts of the other units are likewise brought to the push buttons in multiple so that the actuation of any one of the push buttons 75 to 7 5 inclusive,

short-circuits each of the contacts 33 to 53 inclusive, thereby actuating the circuits of "the corresponding contactor switch, 30 as heretofore described. 1

While I have described my invention and illustrated it in one particular design, I do not wish -it understood that I limit myself to this construction, as it is evident that the applidation of the invention may be varied in many ways within the scope of the following claims.

Claims: I

1. In a direct connected burr mill unit the combination of a rotor, a stator associated with said rotor and having its magnetic face wider than that of said rotor, and means for adjusting the plane of rotation of said rotor with respect to the 2. In a direct connected burr mill unit the combination of a stator, a rotor associated therewith, and having its magnetic face narrower than that of said stator, a shaft driven by said rotor, a burr driven by said shaft, and means ,for raising or lowering said rotor and thereby said shaft and burr.

3. In a direct connected burr mill unit the combination with a stator, of a rotor associated therewith and having its magnetic face narrower than that of said stator, a shaft driven by said rotor, a burr driven by said shaft, and electromagnetic. means for raising and lowering said rotor.

4. In a direct connected burr mill unit the combination of a stator, a rotorassociated .therewith, a shaft driven by said rotor, a

burr driven by said shaft, a second burr associated with said first named burr, means for admitting material to be ground between said burrs, means for lifting said shaft driven burr and means controlled by the passage of material ,to said burrs for .actuatingsaid raising means.

- 5. In a direct connected burr mill. unit the combination with a stator, of a rotor; a support for said rotor, a supporting frame for said support, and engagmg therewith with threaded engagement so the rotation of said support will raise or lower said support, a worm gear, the teeth of which have. straightfaces, carried by said support, a-

worm coacting with said worm gear, an means for rotating said worm.

6. In a direct ceunected'burr null unit we combination of a housing, a stator forming a part of said housing, a rotor associated with said stator and having its magnetic face narrower than that of said stator, a burr directly driven by said rotor, means including a motor and an electrical circuit for raisin or lowering said burr, and a contact in said circuit, and means actuated by the raising of said burr to open said contact, thereby rendering said motor ineffective when said burr has been lifted a predetermined distance.

7. In a direct connected burr mill unit the combination of a stator, a rotor associated therewith and'having its magnetic face narrower than that of said stator, a shaft driven by said rotor, a burr driven by said shaft, means for raising and lowering said rotor and thereby said burr, a motor for operating. said lifting means, a circuit controlling said motor, and means for limiting the vertical motion of said burr.

8. In a direct connected burr mill unit,v

9. In a direct connected burr mill unit the combination with a -motor, of a burr driven thereby, manually operated means for raising or lowering said burr, motor operated means for raising or lowering said burr, and a magnetic clutch interposed between said manually operated means and said motor operated means.

10. In.a direct connected burr mill unit the combination of a motor, a burr driven thereby, a supply spout for said burr, means for raising said burr comprising a motor, an electrical circuit controlling said raising motor, a contact in said circuit, and means controlled by the passage of material through said supply spout for maintaining said contact open while material passes therethrough. i. r

11. In a system of direct connected burr m ll units the combination of multiple burr mlll units; each of said units comprisinga motor, a burr driven thereby, a supply s out for said burr, a lifting means for said urr including a lifting motor and an electrical circuit controlling said lifting motor, a push button controlling contacts connected with the circuits of said burr mill units whereby the actuation of said push button will con- ,trol each of the lifting motors of said burr mill units.

12, I11 a system of direct connected burr mill'units the combination of multiple burr mill units, each of said units comprising a motor, a burr driven thereby, a supply spout for said burr, a lifting means for said burr including a lifting motor' and an electrical circuit controlling said lifting motor, a multiplicity of push buttons, each of said push buttons havin contacts, multiple circuits connecting sai contacts to each of the lift ing motor circuitsof said units whereby the actuation of any one of said push buttons will control the lifting circuit of each of said units.

13. A grinding mill having a rotary memher, a spindle connected with said member for driving the same, means for shifting said spindle in the direction of the axis thereof, and a motor for rotating said spindle, the armature of said motor being secured tosaid spindle to move therewith, and field ieces for said armature of sufficient widt to provide a field for said armature for the various positions of adjustment of said spindle.

14. A grinding mill having a rotary member, a spindle connected to said member for driving the same, means for adjusting said spindle and rotary member in the direction of the axis of said spindle, an armature secured to said spindle, and field pieces of a greater width than saidarmature for providing a magnetic field for such armature for the various positions of adjustment thereof.

15. A grinding mill comprising a pair of grinding discs one of which is movable about an upright axis, an upright spindle for supporting said movableldisc, an'armature connected with said spindle and rotatable therewith todrive said disc, field pieces for said armature of greater extent i ering the spindle and armature for vertically adjusting the disc carried by said spindle.

16. A grinding mill comprising a. vertical spindle, a grinder connected with said spindle and driven thereby, an electric motor having its armature directly connected with said spindle for driving said grinder, a footstep bearing for said spindle, a threaded support for said bearing, and motor driven means for moving said support to shift said spinlle and adjust the position of said 17. A grinding mill comprising an upright spindle, a grinder supported by said spindle, a motor directly connected with said spindle for driving said grinder, a thrust bearing for supporting said spindle, threaded means for raising and lowering said bearing, a motor for driving said threaded means, and a hand actuated device for dr v g said threaded means,

- mature directly connected to sai 18. Agrinding mill comprising an upright spindle, a grinder supported by said spindle, a motor directly, connected with said spindle for driving said grinder, a thrust bearing for supporting said spindle, threaded means for raising and lowering said bearing, a motor for driving said threaded means, a handactuated device for driving said threaded means, and a mechanical clutch interposed between said motor and said threaded means.

19. A grinding mill comprising a pair of grinders arranged one above the other, a vertical spindle supporting one of said grinders,'an electricmotor havin its arspindle for driving the grinder carried thereby, a footstep bearing forsaid spindle, a threaded support for said bearing and means for moving said threaded support to raise and lower the spindle and the grinder carried thereby, whereby the upper grinder is adjusted relatively to the lower grinder.

20.'A grinding mill comprising a pair of grinders arranged one above the other, a vertical spindle supporting one of said grinders, an electric motor having its armature directly connected to said spindle for driving the grinder carried thereby, -a footstep bearing jfOI said spindle, a threaded support for said bearing and means for moving said threaded support to operatively adjust the grinders with respect to each other.

CHARLES TRUMAN HIBBARD'. 

